<!DOCTYPE html>
<html lang="en">

<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
</head>

<body>
    <!-- 计算1-1000之间的累加和，并且打印输出到页面中 -->
    <!-- <script>
        

        let num=0;
        for (let i = 1; i <= 1000; i++){
            num+=i;
        }
        document.write(`${num}`)
    </script> -->

    <script>
        let num = 0, i = 1;

        while (i <= 1000) {
            num += i;
            i++;
        }
        document.write(`${num}`)
    </script>
</body>

</html>